A 4-stroke outboard motor, like any internal combustion engine, requires proper maintenance and care to ensure optimal performance and longevity. One critical maintenance task for outboard motors operated in cold climates is winterization. Winterizing an outboard motor involves taking steps to protect the engine from damage caused by freezing temperatures and lack of use during the winter months. Proper winterization can extend the life of your outboard motor significantly.
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What is winterization?
Winterization refers to the process of preparing an engine for storage during the winter months when it will not be in use. The goal is to protect the internal components from corrosion, freezing of fluids, accumulation of moisture, and any other deterioration that can occur when an engine sits idle for an extended period.
For outboard motors, winterization typically involves draining or treating the fuel system, changing the engine oil and lower unit lubricant, flushing the cooling system, fogging the cylinders, spraying corrosion inhibitors, removing or charging the battery, and properly storing and covering the outboard. Doing this maintenance prepares the motor for the off-season and prevents issues like difficult starting, poor performance, or even complete failure to start when taking the boat out again in the spring.
Does a 4-stroke outboard need winterization?
Yes, just like 2-stroke outboards, 4-stroke outboard motors absolutely require proper winterization as well. Though their combustion process differs, 4-stroke engines still rely on lubrication and have internal components that can be damaged from lack of use in cold temperatures.
While 2-stroke motors require more frequent winterization due to their pre-mixed fuel, 4-strokes still need this maintenance once a year prior to long-term storage. The main systems requiring attention are the fuel system, lubrication system, cooling system, and corrosion protection.
Neglecting to winterize as recommended by the manufacturer will risk serious issues and expensive repairs when attempting to start the motor after months of inactivity. A properly winterized 4-stroke outboard will be protected from seasonal damage and ready for reliable starting and peak performance next boating season.
4-stroke winterization steps
Winterizing a 4-stroke outboard involves several key steps to protect the fuel system, powerhead, cooling system, and exterior components. Here are the main tasks to carry out:
Fuel system winterization
– Stabilize the fuel or drain the system – Fuel left in the tank, lines, and components can go bad or produce varnish and deposits over time. Use a fuel stabilizer additive or drain the fuel completely.
– Change the fuel filter – Replace the external fuel filter so no debris enters the fuel injectors or combustion chambers.
– Spray fogging oil into the cylinders – With the motor running at idle, spray fogging oil into the air intake to coat the cylinders and fuel injectors to prevent rust.
Lubrication system winterization
– Change the engine oil and filter – Old oil lacks the additives and protection needed for long-term storage. Replace with fresh oil and a new filter.
– Replace the lower unit gear lube – Drain and fill the lower unit with new, manufacturer-recommended gear lube to protect the prop shaft and bearings.
Cooling system winterization
– Flush the cooling system – Hook up a hose to the water intakes to flush salt, sediment, and gunk out of the system.
– Drain all water – Ensure all water is drained from the block, hoses, and pumps so no freezing occurs.
– Change the thermostat – Replace the old thermostat to maintain proper coolant circulation when restarting.
– Inspect water pump – Check the impeller and housing for wear and have replaced if needed.
Corrosion protection
– Spray storage sealant – Coat external components like the prop, gear case, controls, etc. with a corrosion inhibitor spray.
– Change zinc anodes – Replace sacrificial anodes which prevent electrolytic corrosion on submerged metal components.
– Lubricate parts – Grease all pivot points, cables, linkages, etc. to prevent rust lockup when stored.
– Remove battery – Take out the battery and store it indoors, on a trickle charger over winter.
Final winter storage
– Thoroughly wash the motor – Get rid of grime, salt, and dirt so it’s clean for storage.
– Touch up paint – Fix any chips or damage to the paint to prevent further corrosion.
– Change gear lube again – One more fill with new gear lube right before final winter storage ensures protection.
– Store properly – Keep in a sheltered area, tilted up, covered, and off the ground if possible.
Following this complete winterization process will ensure your 4-stroke outboard survives the off-season with no issues. It’s time and money well spent compared to the costs of untreated damage come spring.
Professional winterization
While DIY winterization is possible with basic mechanical skills and tools, having your 4-stroke outboard professionally winterized by a certified marine technician is highly recommended.
Trained mechanics have the expertise, equipment, and facilities to properly perform all required winterization tasks. This ensures everything is addressed thoroughly and correctly.
Professional winterization also provides the assurance of dealer-supervised service. Most reputable shops will keep your 4-stroke in heated indoor storage over winter as part of the package. This removes the risks of your own improvised storage methods.
With all factors considered, professional winterization is worth the peace of mind knowing your valuable investment is protected by those best qualified to do so.
Cost of professional winterization
The typical cost for professional winterization averages $250-$500 depending on the size of the outboard. Here are some ballpark estimates for common 4-stroke models:
– 15-25hp – $200-$300
– 30-50hp – $250-$350
– 60-100hp – $300-$400
– 150hp+ – $400-$500+
While the investment may seem steep, one major repair due to frost or corrosion damage could easily exceed the cost of winterization. Think of it as low-cost insurance to protect the much higher price of your entire outboard.
What’s included in professional winterization
At a minimum, you can expect the following services from professional winterization:
– Fuel stabilization treatment
– Engine oil and filter change
– Gear lube change
– Fogging oil sprayed into cylinders
– Cooling system drain and flush
– Corrosion protection spray
– Battery removal and maintenance
– Final wash, inspection and storage preparation
Additional a la carte services may include:
– Fuel filter replacement
– Spark plug replacement
– Lubrication of pivot points
– Propeller removal and refurbishing
– Impeller replacement
– Annode replacement
When to schedule professional winterization
Most marine shops book up quickly as temperatures drop, so it’s advised to schedule service early. Some general guidelines for timing include:
– Freshwater areas – Schedule by mid-October before freezing risk
– Saltwater areas – Schedule by early December before permanent storage
– Northern climates – Schedule by early November before heavy snow
Booking professional winterization by these dates will ensure your outboard gets serviced before the crunch and avoids potential weather delays. You’ll rest easy knowing the work is complete as winter weather arrives.
DIY winterization tips
Is professional service unavailable or out of your budget? With attention to detail and these tips, DIY winterization can be effective:
– Follow your owner’s manual exactly for winterizing – Don’t skip any steps.
– Check for water flow when flushing – Ensure the telltale pee hole has steady flow.
– Stabilize fuel first – This allows it to circulate when fogging the motor.
– Use quality marine fogging oil – Cheap oils lack corrosion protection.
– Grease pivot points after washing – Wet grease attracts dirt rather than repelling it.
– Disconnect and clean battery cables – Prevent corrosion with a wire brush and dielectric grease.
– Use fuel injector cleaner before winterizing – Helps minimize varnish and deposits.
– Seal the intake with plastic and tape – Prevents bugs, debris, and moisture from entering.
– Store under a breathable cover – Let humidity escape while blocking precipitation.
Follow detailed steps, allow plenty of time, and use quality products to get the most protection from DIY winterization.
Prepping the boat
Along with winterizing the outboard itself, the rest of the boat requires preparation for winter storage as well. Some key steps include:
– Thoroughly wash the boat before winterizing the motor – Gets rid of grit and grime that can damage the engine.
– Pump out, drain, and flush the livewell, bilge, and other systems – Eliminates stagnant water that can freeze and cause cracks.
– Fill the fuel tank with treated gas – Prevents condensation from forming a water layer on untreated fuel.
– Empty and clean all storage compartments – Removes food or other organic matter that can mold over time.
– Inspect hoses, clamps, wiring etc. – Make repairs now to prevent costly issues come spring.
– Charge batteries and remove for indoor storage – Maintains a full charge and prevents sulfating.
– Use absorbents and ventilation to keep interior dry – Reduces humidity and chance of mildew over winter.
– Cover tightly and secure to a trailer – Keep out snow, rain, and pests while venting moisture.
Thorough winterization of both outboard and boat completes the seasonal maintenance required to keep your rig in top shape. Don’t neglect the boat when prepping the engine.
Spring restart checklist
After thorough winterization and months of storage, what’s needed to safely restart your 4-stroke outboard in spring? Here are key steps to prep for launch day:
Engine checks
– Remove engine cover and perform visual inspection – Check for any rodent damage, nests, corrosion, leaks, etc.
– Charge and install battery – Ensure a strong 12+ volt charge to crank the starter.
– Check electrical connections – Clean and tighten battery cables, ground wires and other connections.
– Confirm gear lube level – Top off if needed based on leakdown over storage.
– Verify engine oil level – Add oil if low to avoid dry starts.
– Review fuel system – Check for leaks at all points from tank to injectors.
– Check trim/tilt function – Lube pivots if needed and test hydraulic trim and power tilt.
– Spray fogging oil into cylinders – Lubricates cylinders and rings on initial start.
Boat preparation
– Remove all covers and drain plugs – Allows compartments to air out before adding drain plugs.
– Verify bilge pump operation – Ensure pumps activate to drain condensed moisture.
– Test electronics and gauges – Check for low battery warnings, inoperable gauges, faulty wiring.
– Examine hull carefully – Look for cracks, blisters or damage below the waterline.
– Reinstall batteries – Use fresh water to reactivate batteries after winter storage.
– Attach engine to boat – Securely mount the motor as recommended by the manufacturer.
– Open seacock and check hoses – Allows raw water flow to the engine.
– Confirm prop installation – Spin the prop to ensure no winter damage or fishing line tangled.
Following this checklist ensures you address any issues from storage and confirms seaworthiness before launching. Be thorough – catching problems at the ramp is much harder!
First launch of the season
The maiden voyage of the year requires extra diligence after outboard winterization. Here are tips for a smooth first launch:
– Start the engine well in advance – Allow time for warmup and checks before launching.
– Let it idle 5+ minutes before going to full throttle – Gives the engine time to circulate and build oil pressure.
– Keep an eye on gauges – Monitor for excessive temperature, low oil pressure or other anomalies.
– Go through RPMs slowly – Avoid aggressive throttle and shift points until engine is fully warmed.
– Stay near the launch point – Don’t go far until you’ve verified normal operation for at least 15-20 minutes of runtime.
– Watch the telltale closely – Continuous steady spray from the pee hole verifies water pump operation.
– Keep an ear out – Listen closely for odd noises that could indicate an issue.
– Check components after docking – Inspect for leaks, loose parts, overheating signs, etc..
The first outing is a shakedown cruise – taking it slow and easy lets you confirm normal operation after winter downtime. Stay alert and don’t push it until your motor is ready.
Summary
While required maintenance may seem tedious, proper winterization is crucial to keeping your 4-stroke outboard running in peak form. Taking the time to thoroughly follow winterization steps, or have it professionally done at a dealership, will pay off with years of trouble-free boating.
Neglected winterization often leads to catastrophic failures and thousands in repairs. With a well-winterized motor, you can be confident of reliable performance all season long. Your boat and wallet will thank you!